Transcriptome Analysis of Medicinal Plant Salvia miltiorrhiza and Identification of Genes Related to Tanshinone Biosynthesis

Salvia miltiorrhiza Bunge, which is a Lamiaceae family plant of traditional Chinese medicine, accumulates abietane-type diterpenoids of tanshinones and has been used for treating neuroasthenic insomnia and cardiovascular diseases. Tanshinones were reported to accumulate mainly in S. miltiorrhiza root and trace amount in aerial tissues, therefore we profiled and compared S. miltiorrhiza root and leaf transcriptomes by Roche’s 454 GS-FLX pyrosequencing platform, to identify biosynthetic enzymes and transcriptional regulators. Totally 64,139 unigenes were assembled, and 5,424 unigenes showed distinct transcript abundance between leaf and root. The transcripts of copalyl diphosphate synthase (SmCPS), kaurene synthase-like (SmKSL) and CYP76AH1, encoding critical enzymes for tanshinones biosynthesis, were detected specifically in root. Candidate genes involved in downstream of tanshinone biosynthetic pathway, including cytochrome P450 monooxygenases, dehydrogenases and reductases, were also discussed. Our dataset for root and leaf of S. miltiorrhizarepresents the major transcriptome changes and provides a valuable resource for further studies of the tissue-specific tanshinones biosynthesis and regulation.